Gear pump



1949- J. A. VERTSON 8 ,917

GEAR PUMP Filed March 6, 1945 Ff I 44 27 T5111- i w .L

144 i 17 2 I fi 59 3/ 55 INVENTOR.

Jada/4. 14-27250 ATTORNEYS Patenteci Got. i8, 149

UNITED STATES PATENT OFFICE GEAR PUMP John A. Vertson, Brea, Calif.

Application March 6, 1945, Serial No. 581,199

- ll Claim. 1

This invention relates to improvements in pumps, and particularly to that class of pump generally referred to as gear-type pumps.

A primary object of the invention is to provide an improved gear-type pump wherein the gears or rotor elements are so arranged and constructed that pressure effective thereon are largely, if not entirely, balanced and neutralized. In the conventional gear-type pump there is a housing providing communicating chambers in which the gears are rotatable. The inlet is arranged on one side of the meshing gears and the fluid is expelled through an outlet on the opposite side of the point of engagement between the gears. The pressure in the outlet is, of course, materially greater than the pressure in the inlet and this outlet pressure is effective to urge the gears away from each other within the housing with the result that parts on which the gears are rotatable are subjected to extreme wear and leaking clearances develop which in a relatively short time reduce the efficiency of this type of pump. The improved pump is so constructed that the outlet pressure is conducted through the gears from the point where it is developed so that each gear is subjected on opposite sides thereof to the outlet pressure. In this way the outlet pressure has a balancing or neutralizing effect on each of the gears so that in effect the gears are virtually floating within the housing. Consequently wear of the supports for the gears is practically eliminated and the wearing of any clearances between the teeth of the gears and the housing is likewise eliminated so that the efficiency of the pump is maintained at a maximum for a very long life.

Another object of the invention is to provide an improved hydraulic pump of the gear-type which is of relatively simple, durable design, and which can be economically manufactured and assembled.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure 1 is a vertical section through the pump embodying the present invention;

Fig. 2 is a transverse vertical section taken substantially upon the line 22 upon Fig. 1; and

Fig. 3 is a partial view in elevation illustrating a detail of construction Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the improved pump comprises a suitable body 10 to which end members II and i2 are connected which, in turn, are provided wtih end caps [3. The body provides two circular communicating chambers 14 and I5 within which there are rotatable gear-shaped rotors I 6 and I! which are meshing with each other opposite an inlet 18. These rotors are in the shape of gears. the outer ends of the teeth being in wiping contact with portions of the interior of the body as indicated in Fig. 2. Slots l8 are formed in the gears between the teeth and extend radially inward. The lengths of these slots are but small portions of the lengths of the entire gears. 'I'he gears or rotors are rotatably mounted on hollow arbors 20 and 2| which extend through the end plate H and which are held against rotation relatively thereto by means of a keeper 22. The opposite end of the lower arbor 2| is seated in the end plate l2. The upper arbor 20 terminates adjacent the splined end 23 of a drive shaft 24 which is sealed against leakage thereabouts by means of a seal 25. The

- splined end '23 fits within an extended hub 26 on the upper gear or rotor l6 and this hub is rotatably mounted within an anti-friction bearing 21.

Fluid which enters the housing through the inlet l8 reaches a low pressure locality 28. This fluid enters the spaces between the gear teeth and is carried around the two chambers 14 and I5 by the gear teeth to a high pressure locality which is located near the point where the rotors are in mesh with each other but on the opposite side of the point of engagement from the inlet I8. Slots 30 and 3| extend diametrically across the hollow arbors 20 and 2| from the locality of high pressure indicated at 29 to outlets 32 and 33 which. in turn, communicate with a common outlet 34 leading from the housing. The widths of these slots 30 and 3| is slightly greater than the combined width of a slot l9 and its adjoining tooth so that as the rotors rotate the slots will be constantly open at both ends for the passage of fluid therethrough from the locality of high pressure 29 to the outlets 32 and 33. In this manner fluid is taken into the housing from inlet l8 carried around the chambers l4 and l 5 to the locality of high pressure at 29 and then is forced through the the inlet.

3 tralized. The areas on the rotors exposed by the outlets and which are consequently subject to outlet pressures are approximately equal to those areas on the rotors that are subject to the hi pressure in the high pressure zone '28. Consequently there is no net effective force on either of the rotors tending to displace them from their axes of rotation. Wear of the rotors on their respective arbors-is consequently reduced to a minimum and wear between the ends of the teeth and the interior of the housing is likewise reduced to a minimum. I find it advantageous to relieve the interior of the housing as indicated at 35 diametrically opposite the inlet port. The wiping engagement between the rotors and the interior of the housing ordinarily need not exceed a distance across the tops of three teeth. I preier to provide grooves 36 and 31 on the interiors of the end plates II and 12 which communicate with annular grooves 38 and 39 around the ends of the gears and these annular grooves in turn communicate with grooves 40 that are exposed to By means of these grooves the inlet pressure whatever it may be is transmitted to the relieved portions 35 so that pressures diametrically across the rotors from the inlet will be equal or substantially so. Small holes 4| may be formed in the hub of the upper rotor to conduct off any leakage and to supply lubricant to the bearing 21.

From the above-described construction it will b appreciated that the improved pump is so designed that pressures efiective on one side of each rotor will be balanced or substantially balanced by an equal pressure on the opposite side of the rotor thus materially reducing any tendency of the pump to wear on its arbors or to wear between the ends of the teeth and the interior of the housing. Consequently the pump as originally constructed may have a very close fit of its parts and such fit will be retained throughout a very long life. By reason of the close fitting of the parts throughout the long life of the pump and a high degree of efllciency is obtainable.

Various changes may be made in the details of 4 construction without departing from the spirit and scope of the invention as defined by the appended claim.

I claim:

A pump comprising a housing providing two mutually communicating rotor chambers, gearshaped rotors rotatably mounted on arbors in said chambers respectively and mutually meshing with each other, there being an inlet to the housing on one side or the zone of mesh or the rotors. said housing providing walls in close proximity to the ends or the teeth on the rotors so that as the rotors rotate a high pressure zone will be developed on the opposite side of the zone of mesh from the inlet. there being passages in the rotors between the teeth thereof, there being diametrical passages through the arbors the ends of which are adapted to register consecutively with the-passagesbetween the teeth as the rotors rotate, said housing providing outlets adjacent the peripheries of the rotors arranged diametrically opposite across the rotors from the zone of high pressure and said arbor passages together with said passages between the teeth providing communication between said zone and said outlets whereby the effects of pressures on the rotors in the zone of high pressure and in the outlets will be substantially neutralized, and means whereby the rotors may be rotated.

JOHN A. VERTSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATEN'IS Number Name Date 2,338,065 Ungar Dec. 28, 1943 2,400,485 Cardillo Ma 21, 1946 FOREIGN PATENTS Number Country Date 300,832 Germany Sept. 18, 1917 

